# Migrate MinIO bucket: Generated downloads

## Summary

Move object storage from MinIO bucket to Ample, one component at a time. Destination verified on Ample: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Source procedure: Inventory the bucket with `mc du` or `rclone size`. Not migrated automatically: MinIO bucket policies, versioning, replication, ILM rules and notifications are not migrated. Cutover: Switch the app's S3_* environment to the Ample bucket with a redeploy, verify reads and writes, keep MinIO read-only until confirmed. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

## Infrastructure requirements

- [S3-compatible object storage](/discover/primitive/s3-compatible-object-storage): verified (Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.)

## Prerequisites

- Authorized access to the MinIO bucket source and its export tooling
- An inventory of every component in scope and out of scope
- A validated backup or copy before any cutover
- An Ample account token with servers:write, buckets:write

## Exact tested configuration

- template: `node-22`
- runtime: `node`
- size: `s-1vcpu-1gb`
- install: `npm install`
- build: `npm run build --if-present`
- start: `npm run start`

## Steps

1. **Inventory the source.** List what MinIO bucket provides beyond the component you are moving. Out of scope here: MinIO bucket policies, versioning, replication, ILM rules and notifications are not migrated.
2. **Source step 1.** Inventory the bucket with `mc du` or `rclone size`
3. **Source step 2.** Copy objects with `mc mirror` or `rclone sync` from MinIO to the Ample bucket endpoint using the issued credentials (path-style)
4. **Source step 3.** Verify a sample of objects by size and checksum after the copy
5. **Create the destination bucket and copy.** Create the bucket, copy with rclone or the S3 CLI in path-style mode using the issued credentials, then pass the credentials to the app as encrypted S3_* variables.

```
   ample bucket create --name <bucket-name>
   ```
6. **Validate before cutover.** Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/generated-downloads).
7. **Cut over.** Switch the app's S3_* environment to the Ample bucket with a redeploy, verify reads and writes, keep MinIO read-only until confirmed.
8. **Rollback.** Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

## Tested examples

- **Express pattern fixture (destination)** (tests/deploy-canaries/express-patterns): Verified destination basis: generated downloads.

## Success checks

- destination app responds on its public URL (`/` on the live URL, expect ample canary express patterns)
- generated-downloads check from the destination example (`/p/generated-downloads` on the live URL, expect see the pattern fixture checks)
- data or object counts and checksums match the source

## Limitations

- Documentation only: nothing is executed automatically and no execution binding is offered.
- The source-side procedure is documented from MinIO bucket's standard tooling and was not executed in this catalog's evidence; the destination side was verified with the pattern fixture.
- No full source-product parity is claimed: MinIO bucket policies, versioning, replication, ILM rules and notifications are not migrated.
- Verified on the node-22 template at s-1vcpu-1gb; region, compliance and request-duration limits are unknown.
- PutObject and GetObject with path-style addressing are verified; bulk copy tooling and other S3 operations are not.